The present disclosure is generally directed to methods and compositions for clearing and cleaning enteral feeding tubes. More particularly, the composition is an ingestible gel composition that comprises enzymes for degrading buildup in enteral feeding tubes, carrageenan, and divalent metal ions or a source thereof. The carrageenan present in the composition stabilizes the enzymes at room temperatures, allowing for long-term storage of the composition. Upon injecting the gelled composition into the feeding tube, body heat from the patient melts the gel, and the enzymes are released to act on debris present in the lumen of the feeding tube.
Many acutely and chronically ill patients cannot properly chew or swallow their food or medication, and as a result may become severely malnourished. Consequently, food and/or medication must be delivered to the patient in a different manner. Gastroenterologic feeding tubes have been known for years and have been used to provide nutrition and medication to patients who are unwilling or unable to obtain nutrition by swallowing.
Feeding tubes may be inserted into the stomach (gastrostomy tubes) or intestines (jejunostomy tubes) by any one of a number of different methods. Generally, a catheter is placed in the body by way of the mouth and is pulled or pushed downward into the stomach and either left there or is pushed further down into the jejunum of the small intestine. The feeding tubes may also enter the body either by way of the nasal passageway, or through open surgical, endoscopic, laproscopic, or radiologic techniques. For example, a feeding tube may be surgically implanted through the abdomen. The most common type of feeding tube is a percutanenous endoscopic gastronomy (PEG) tube, which is inserted into the patient endoscopically.
During the use of enteral feeding tubes, residual food, proteins, starches, cellulose, and/or medication may accumulate in and block the feeding tube. Occlusions in general can be caused by inappropriate administration of medications, poor flushing techniques, thick formulas, or reflux of gastric or intestinal contents up into the tube. In addition to preventing food composition from passing through the tube to the stomach, such blockages also provide a ready site for the growth and multiplication of bacteria. It is therefore important to regularly clean the feeding tube to prevent such blockages.
A variety of means are known for cleaning enteral feeding tubes. For example, U.S. Pat. No. 4,894,056 describes a method and device for restoring the patency of feeding tubes that involves contacting occlusions in the tubes with a combination of solubilizing agents and mechanical force. Other techniques may involve the use of pressurized fluids or suction to flush the tube. However, these techniques may be time consuming, run the risk of rupturing the tube if high pressure is used, and may involve removal and reinsertion of the tube, causing discomfort to the patient.
Enzyme solutions have also been used to maintain or restore feeding tube patency. However, while enzymes themselves may be an effective means of preventing or dissolving blockages in feeding tubes, there are drawbacks to the use of enzymes solutions. For instance, many biological materials, such as enzymes, are known to have a limited shelf life. This is generally considered to be a result of enzyme instability at storage temperature, e.g., at room temperature. The shelf life of certain enzymes may be extended by storing them at refrigeration temperatures, but even under refrigeration, relatively short shelf lives are common.
As will be appreciated, biologically active proteins, such as enzymes, are generally folded in a complex three dimensional manner which is unique to each protein. The ultimate structure of an enzyme may be affected by a number of environmental factors; for example, temperature, pH, the presence or absence of certain co-factors or metals, the presence of oxygen, oxidizing or reducing agents, and the presence of water or moisture. Where conditions are not optimal, an enzyme may not form properly or may denature such that its biological function is lost or is at least diminished.
Enzyme flushes are normally made in solution. However, water may hydrolyze the enzymes present in the flush solution in a time and temperature dependent manner, resulting in denaturation and potential loss of enzyme function. One way to maintain enzyme stability over extended periods of time is to incorporate chemical inhibitors into the flush solution, which may act to hold the enzymes in the solution inactive until use. However, since the flush solution used to clean enteral feeding tubes will ultimately end up being ingested by the patient, it is often not desirable to incorporate chemical inhibitors into the solution. Furthermore, dehydrating enzyme solutions may not improve their stability, as during dehydration and at the high temperatures at which known dehydration procedures may occur, the proteins may also be denatured.
There is thus a need for an enteral feeding tube cleaning composition which has an extended shelf life, and can also be safely ingested by a patient.